چکیده انگلیسی

Abstract
The word- and nonword-learning abilities of toddlers were tested under various conditions of environmental distraction, and evaluated with respect to children's temperamental attentional focus. Thirty-nine children and their mothers visited the lab at child age 21-months, where children were exposed to fast-mapping word-learning trials and nonlinguistic sequential learning trials. It was found that both word- and nonword-learning were adversely affected by the presentation of environmental distractions. But it was also found that the effect of the distractions sometimes depended on children's level of attentional focus. Specifically, children high in attentional focus were less affected by environmental distractions than children low in attentional focus when attempting to learn from a model, whereas children low in attentional focus demonstrated little learning from the model. Translationally, these results may be of use to child health-care providers investigating possible sources of cognitive and language delay.

نتیجه گیری انگلیسی

. Results
Children were divided into groups of “low focused” and “high focused” children using a median split applied to the focused attention scale of the ECBQ, which is referred to below as attentional focus. The result was that 19 children were classified as low focused, and 20 were classified as high focused. Means and standard deviations of children's performance on the word- and nonword-learning tasks, in the low and high focused groups, as a function of distraction condition, are presented in Table 2, Table 3 and Table 4.
Table 2.
Means and standard deviations of word-learning performance on fast-mapping task by distraction condition and level of focus
Distraction condition Level of focus
Low High
M S.D. M S.D.
Baseline (no distraction)
Comprehension 2.75 1.32 2.71 1.28
Generalization 2.91 1.50 3.12 1.26
Cognitive distraction
Comprehension 2.63 1.48 2.69 1.25
Generalization 2.94 1.35 3.29 0.87
Social distraction
Comprehension 1.88 1.22 2.62 1.22
Generalization 2.31 1.20 3.19 1.20
Mechanical distraction
Comprehension 1.66 0.93 2.05 1.54
Generalization 2.81 1.36 2.88 1.40
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Table 3.
Means and standard deviations of make-a-rattle sequence learning task performance by distraction condition and level of focus
Condition Level of focus
Low High
M S.D. M S.D.
No distraction
Premodel
Number of actions 4.85 3.21 4.50 4.04
Ordered pairs of actions 2.62 1.66 1.75 1.91
Postmodel
Number of actions 6.15 3.02 7.25 3.99
Ordered pairs of actions 3.92 2.33 4.75 2.61
Distraction
Premodel
Number of actions 5.17 3.31 5.23 3.44
Ordered pairs of actions 2.83 2.14 2.92 1.89
Postmodel
Number of actions 4.50 1.76 6.23 4.15
Ordered pairs of actions 2.50 0.55 3.85 1.91
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Table 4.
Means and standard deviations of feed-self sequence learning task performance by distraction condition and level of focus
Condition Level of focus
Low High
M S.D. M S.D.
No distraction
Premodel
Number of actions 2.67 2.29 2.42 2.47
Ordered pairs of actions 1.56 1.94 1.58 2.68
Postmodel
Number of actions 6.67 5.94 6.67 3.34
Ordered pairs of actions 5.33 5.39 5.08 3.20
Distraction
Premodel
Number of actions 3.58 2.97 0.57 1.13
Ordered pairs of actions 2.58 3.03 1.00 1.53
Postmodel
Number of actions 4.42 4.70 7.14 3.98
Ordered pairs of actions 3.25 4.27 4.29 4.03
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2.1. Word-learning performance
A preliminary analysis of variance involving order of distraction condition, revealed no significant main or interaction effects involving the order factor. Hence, word learning was collapsed across distraction orders. There was also no difference between the two types of social distracter, so these conditions were also collapsed. In order to test the effects of environmental distractions on word-learning performance, and to explore whether level of child attentional focus moderated any distraction effects, a 4 (distraction condition) × 2 (word-learning phase) × 2 (level of attentional focus) mixed design analysis of variance was conducted on children's word-learning performance, with distraction condition and word-learning phase serving as within-subjects measures. Because two children did not have complete scores across all of the 8 word-learning conditions along with completed ECBQs, analyses involving the word-learning task were based on 37 children. These two children were missing data in one or more of the word-learning conditions, generally as a result of experimenter error, and included cases where a tray failed to be presented or the wrong tray was presented.
2.1.1. Effects of distracters on word learning
As in Dixon and Salley (submitted for publication), results revealed significant main effects for distraction condition [F(3,33) = 5.31, p = 0.004, η2 = 0.33] and word-learning phase [F(1,35) = 17.51, p = 0.000, η2 = 0.33]. Both of these effects are discussed in more detail in the next paragraph. However, unlike in Dixon and Salley, a distraction condition × word-learning phase interaction effect was not found in the present study. Dixon and Salley found that improved performance during generalization, as compared to initial comprehension, was limited to the no distraction condition. In the present study, however, performance during generalization was higher than during comprehension, without regard to distraction condition.
To break down the distraction condition, the main effect reported above, planned comparisons (see Fig. 1) revealed that overall word-learning performance in the no distraction condition, collapsed across word-learning phase, was significantly higher than performance in either the social distraction condition (LSD adjusted p = 0.040) or the mechanical distraction condition (LSD adjusted p = 0.015). Performance in the cognitive distraction condition was also higher than in the mechanical distraction condition (p = 0.006), and trended toward being higher than in the social distraction condition (p = 0.087). However, there was no difference in word-learning performance between the baseline and cognitive distraction conditions. Thus, it appears that a 25% increase in the stimulus array in the cognitive distraction condition is not sufficiently attention-burdening so as to impede novel word learning. Consistent with Dixon and Salley (submitted for publication), there was also no difference in word learning between the social and mechanical distraction conditions.
Word-learning performance by level of focus and distraction condition.
Fig. 1.
Word-learning performance by level of focus and distraction condition.
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2.1.2. Attentional focus
Of primary interest in the present study was whether children's level of attentional focus would moderate the effects of environmental distractions on word learning. Interestingly, the omnibus distraction condition × level of focus interaction effect failed to reach significance [F(3,33) = 1.72, p = 0.182, η2 = 0.14]; however, consideration of planned comparisons revealed that there were differences. Specifically, as depicted in Fig. 1, low focus children showed a significant decline in word learning in the social distraction condition (p = 0.008) and a nearly significant decline in the mechanical distraction condition (p = 0.063), relative to baseline. Low focus children also showed significant drops in performance in both the social (p = 0.045) and the mechanical (p = 0.055) conditions relative to the cognitive condition. In contrast, high focus children showed a drop in performance only in the mechanical distraction condition, and then only relative to the cognitive distraction condition (p = 0.036). This pattern of finding seems to suggest that to the extent that attentional focus may have moderated the influence of environmental distractions on word learning, it did so primarily in the social distraction condition.
2.1.3. Summary
These findings support the general contention that environmental distractions can inhibit word learning. Results from the present study suggest further that at least a portion of the variance in word-learning performance can be attributed to children's attentional focus. In particular, the word learning of children high in attentional focus appears to be less adversely impacted by the presence of a social environmental distraction than children low in attentional focus. This finding is consistent with past literature reporting relationships between attention and language development (e.g., Dixon & Shore, 1997; Dixon & Smith, 2000). However, these results fail to replicate previous findings Dixon and Salley (submitted for publication) that children learning novel words in the absence of environmental distractions are better able to generalize those words than children learning them in the presence of sudden onset distractions.
2.2. Nonword-learning tasks
2.2.1. Make-a-rattle task
In order to test for the effects of environmental distractions on children's abilities to learn an enabling relations sequence, and to observe whether children's level of attentional focus would moderate such an effect, two 2 (modeling: pre- versus postmodel) × 2 (distraction condition: presence versus absence) × 2 (level of attentional focus: low versus high) mixed design analyses of variance were conducted on children's make-a-rattle performance, with distraction condition and level of focus serving as between subjects factors. Two dependent measures of interest were: number of target actions performed and number of pairs of target action performed in sequence.
For pairs of target action performed in sequence, performance was significantly higher after the model than before it, as evidenced by a significant main effect of modeling [F(1,36) = 9.45, p = 0.004, η2 = 0.21]. Total number of target actions was not significantly affected by the model.
Pairs of target actions in sequence was involved in two additional effects. First, a significant modeling × distraction condition interaction effect [F(1,36) = 5.48, p = 0.025, η2 = 0.13], revealed that viewing the model only improved performance in the no distraction condition (see Fig. 2). Thus, although the presence of a distraction did not adversely influence make-a-rattle performance overall, it did eliminate the facilitating effect of the model.
Performance in the make-a-rattle task pre- and postmodel by level of attentional ...
Fig. 2.
Performance in the make-a-rattle task pre- and postmodel by level of attentional focus and distraction condition.
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The second effect of interest was a modeling × attentional focus interaction effect which approached statistical significance [F(1,36) = 3.43, p = 0.072, η2 = 0.09]. This interaction hinted that the effect of the model might also be dependent on children's level of attentional focus. Specifically, high focused children trended toward benefiting from the model more than did low focused children (see Fig. 2).
2.2.2. Feed-self task
In order to test for the effects of environmental distractions on children's abilities to learn a conventional, noncausal sequence, and to observe whether children's level of attentional focus would moderate the effect of environmental distracters in this nonword-learning task, two 2 (modeling: pre- versus postmodel) × 2 (distraction condition: presence versus absence) × 2 (level of focus: low versus high) mixed design analyses of variance were conducted on children's feed-self performance; again, with distraction condition and level of focus serving as between subjects factors. As with the make-a-rattle task, the two dependent measures included in the analyses were number of target actions performed and number of pairs of target action performed in sequence.
However, unlike in the make-a-rattle task, modeling significantly increased both number of pairs of target actions in sequence [F(1,36) = 15.95, p = 0.000, η2 = 0.31] and total target actions [F(1,36) = 29.47, p = 0.000, η2 = 0.45], compared to premodel performance.
Two other significant effects were of interest. First, a significant modeling × attentional focus interaction effect [F(1,36) = 4.31, p = 0.045, η2 = 0.21] revealed that modeling effected more total target actions for children high in attentional focus than for children low in attentional focus. Moreover, and second, this interaction effect itself interacted with distraction condition [F(1,36) = 3.62, p = 0.065, η2 = 0.09], resulting in a three-way interaction effect. Though complicated, this three-way interaction revealed that the effect of the model on feed-self performance was weakest in the distraction condition for children low in attentional focus. Fig. 3 illustrates these effects for total number of target actions. Interestingly, post-hoc analyses revealed that children high in attentional focus had significantly lower performance before exposure to the model than children low in attentional focus (Sidak adjusted p = 0.046). That is to say, when children low in attentional focus were initially given the feed-self stimuli, they seemed more inclined to begin performing target actions with those items than children high in attentional focus. This finding raises the possibility that our attentionally focused children were more inclined to wait for adult direction in an otherwise ambiguous situation than were children low in attentional focus. But further research is needed to evaluate this possibility.
Performance in the feed-self task pre- and postmodel by level of attentional ...
Fig. 3.
Performance in the feed-self task pre- and postmodel by level of attentional focus and distraction condition.
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Finally, it should be noted that a cursory review of Fig. 3 seems to indicate premodel differences in feed-self performance across the two distraction conditions, for children both high and low in attentional focus. However, post hoc analyses revealed that children low in attentional focus in the distraction condition did not differ significantly in premodel performance from children low in attentional focus in the nondistraction condition. The same was true for high focus children. On the other hand, high focus children differed from low focus children in terms of premodel performance in the distraction condition (LSD adjusted p = 0.019), whereas no corresponding difference in the nondistraction condition was detected. This finding suggests that our high focus children differed in some way from our low focus children in the distraction condition, in a way that was not mirrored in the nondistraction condition. The source of such a difference is not possible to determine because all children were assigned randomly to condition. It is interesting, nevertheless, that children whose premodel performance was so low demonstrated a 14-fold postmodel increase. This increase suggests that their initially low performance was not a disadvantage once the modeled behavior was presented to them.
2.2.3. Summary
Data from the nonword-learning tasks revealed that environmental distractions impacted the extent that children were able to acquire and reproduce environmental contingencies, in a manner that generally mirrored word-learning performance. Furthermore, as in the word-learning tasks, it appears that attentional focus may have moderated the adverse impacts of environmental distractions on children's learning of nonlinguistic contingencies, such that children high in attentional focus were less affected by environmental distractions when learning either linguistic or nonlinguistic contingencies. Because attentional focus seemed to play a similar moderating role across both nonword-learning tasks, it does not appear that either causally or arbitrarily linked event sequences are particularly associated with the moderating role of attentional focus. It also does not appear that vocabulary acquisition is any privileged position when it comes to learning environmental contingencies in the presence of environmental distractions.